Seal for lead bore of an implantable medical device

Abstract

A seal for use within a lead bore of an implantable medical device for forming a seal against an implantable medical lead inserted into the lead bore includes an inner cylinder that engages a lead body. The inner cylinder is surrounded by a gap between an outer cylinder of the seal or a surrounding structure of the implantable medical device. The inner cylinder has freedom of movement within the gap such that off-axis movement of the lead body relative to a centerline of the lead bore causes movement of the inner cylinder that provides the seal. In this way, a sealing engagement with the lead body is maintained during such off-axis movement of the lead body.

Description

TECHNICAL FIELD

[0001] Embodiments relate to seals placed in lead holes of implantable medical devices. BACKGROUND

[0002] Lead holes of implantable medical devices include one or more electrical connectors that form electrical connections with corresponding electrical contacts on proximal ends of implantable medical leads that are inserted into the lead holes. Conductors within the implantable medical leads carry electrical signals between the electrical contacts and electrodes located near distal ends of the leads. These electrical signals can be stimulation signals that are delivered to tissue at the distal electrodes. Additionally or alternatively, these signals can be sensed physiological signals that occur at the distal electrodes that are delivered to sensing circuitry of the implantable medical device.

[0003] When carrying stimulation signals or sensed signals on implantable medical leads, it is useful to electrically isolate the electrical contacts on the proximal ends from each other and from body tissue surrounding the implantable medical device. For example, such isolation helps to deliver signals intended for a given proximal contact and corresponding distal electrode to that proximal contact and distal electrode while largely preventing any amount of signal leakage to the body or other proximal contacts at the proximal end of the lead. Likewise, such isolation helps to deliver sensed signals obtained at a given distal electrode to circuitry paths of the implantable device that correspond to proximal contacts paired with that distal electrode while largely preventing any amount of signal leakage to the body or other proximal contacts at the proximal end of the lead. Likewise, other electrical signals present near the implantable medical device can largely be prevented from leaking into the lead hole.

[0004] Electrical isolation is provided by the presence of seals within the lead holes of implantable medical devices. These seals are typically present between adjacent electrical connectors within the lead holes and also at the lead hole entrances at the surface of the implantable medical device. These seals can typically provide a circumferential protrusion having an open center that is smaller in diameter than the lead diameter such that contact is made at the open center with the lead body to provide a seal around the lead body.

[0005] When forming a seal, movement of the lead body in a radial direction can stretch the open of the protrusion, which can form a small gap that allows a small amount of body fluid to pass through the seal. This lead body movement can occur during implantation or during normal body movement of the patient. While a small amount of fluid can not always be a point of concern, in situations where the electrical signal of interest is already very small and other nearby signals are large, such as when a relatively small neural signal of the brain is sensed in the presence of a relatively large cardiac signal near the implantable medical device, a small amount of fluid intrusion into the lead hole can result in enough signal leakage to cause problems. SUMMARY

[0006] Embodiments address such issues and others by providing a seal for an implantable medical device that includes a cylindrical portion that engages a lead body, where the cylindrical portion has a freedom of movement relative to a portion of the seal that is held in a fixed position relative to a lead bore. The cylindrical portion is not a contact point with the lead body formed by a radially inward protrusion having a fixed position, but rather extends along a length of the lead body such that during movement of the lead body in a radial direction, the cylindrical portion also moves to maintain contact with the lead body.

[0007] Embodiments provide a seal for an implantable medical device that includes a body. The body includes a first cylinder that is elastic and defines a seal bore having a centerline, the first cylinder having an outer diameter. The body further includes a wall portion coupled to the first cylinder and having an outer surface that forms a plane that intersects the centerline, the first cylinder being movable relative to the wall portion to allow a change in an intersection angle between the centerline and the plane.

[0008] Embodiments provide an implantable medical device that includes a housing defining a lead bore having a lead bore diameter and a circuit located within the housing. The implantable medical device further includes an electrical connector positioned within the lead bore and electrically coupled to the circuit and a seal body coupled to the housing. The seal body includes a first cylinder that is elastic and defines a seal bore having a centerline, the first cylinder being positioned within the lead bore and having an outer diameter at a location of the first cylinder that is less than the lead bore diameter. The seal body further includes a wall portion coupled to the housing, the wall portion being coupled to the first cylinder and having an outer surface that forms a plane that intersects the centerline, the first cylinder being movable relative to the wall portion to allow a change in an intersection angle between the centerline and the plane.

[0009] Embodiments provide a seal for an implantable medical device that includes a body. The body includes a first cylinder that is elastic and defines a seal bore having a centerline, the first cylinder having an outer diameter. The body further includes a wall portion coupled to the first cylinder, where the first cylinder has a rest position in which the centerline forms a first angle relative to a first plane, the first cylinder being movable relative to the wall portion to allow a change in the first angle of the centerline relative to the first plane.

[0010] Embodiments provide an implantable medical device including a housing defining a lead bore having a lead bore diameter and a circuit positioned within the housing. The implantable medical device also includes an electrical connector positioned within the lead bore and electrically coupled to the circuit and a sealing body coupled to the housing. The sealing body includes a first cylinder that is elastic and defines a sealing bore having a centerline, the first cylinder positioned within the lead bore and having an outer diameter at a location of the first cylinder that is less than the lead bore diameter. The sealing body also includes a wall portion coupled to the housing, the wall portion coupled to the first cylinder, wherein the first cylinder has a rest position in which the centerline forms a first angle relative to a first plane, the first cylinder movable relative to the wall portion to allow the first angle of the centerline relative to the first plane to change.

[0011] Embodiments described herein are primarily discussed in relation to a header mounted to a housing of an implantable medical device for receiving a proximal end of a lead. However, this should not be seen as limiting. The sealing elements described can be incorporated into any aspect of an implantable system that requires a sealing element coupled to a movable member that is movable relative to a wall portion of the sealing element. For example, such sealing elements can equally be used at a distal end of a lead extension having a lead bore for receiving a proximal end of a lead. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 An example of an implantable medical system including an implantable medical lead and an implantable medical device that can include a sealing member is shown in accordance with various embodiments.

[0013] Figure 2 A front view of an example of a sealing member that can be used in an implantable medical device is shown.

[0014] Figure 3 A cross-sectional front view of the sealing member of Figure 2 is shown, showing an inner cylinder present within the sealing member.

[0015] Figure 4 A back view of the sealing member of Figure 2 is shown.

[0016] Figure 5 A cross-sectional back view of the sealing member of Figure 2 is shown.

[0017] Figure 6 A top view of the sealing member of Figure 2 is shown.

[0018] Figure 7A A cross-sectional top view of the sealing member of Figure 2 is shown, and also showing a lead body centrally aligned within the sealing member.

[0019] Figure 7B A cross-sectional top view of the seal of Figure 7A is shown with a non-perpendicular relationship of the centerline of the seal to the plane.

[0020] Figure 8A A cross-sectional top view of the seal of Figure 2 is shown with a non-perpendicular relationship of the centerline of the seal to the plane.

[0021] Figure 8B A cross-sectional top view of the seal of Figure 8A is shown with a non-perpendicular relationship of the centerline of the seal to the plane.

[0022] Figure 9 A cross-sectional top view of a second example is shown, where the inner cylinder has an asymmetric rear edge, while coupled to the front wall portion.

[0023] Figure 10 A cross-sectional top view of a third example is shown, where the inner cylinder has an asymmetric rear edge, while coupled to the front wall portion, and where there is no additional seal beyond the inner cylinder.

[0024] Figure 11 A cross-sectional top view of a fourth example is shown, where the inner cylinder has an asymmetric front edge, while coupled to the rear wall portion.

[0025] Figure 12 A cross-sectional top view of a fifth example is shown, where the inner cylinder has an asymmetric front edge, while coupled to the rear wall portion, and where there is no additional seal beyond the inner cylinder.

[0026] Figure 13 A cross-sectional top view of a sixth example is shown, where the inner cylinder is coupled to the front wall and lacks an inner protrusion but has a surface coating.

[0027] Figure 14 A cross-sectional top view of a seventh example is shown, where there is no additional seal beyond the inner cylinder, and where the inner cylinder is coupled to the front wall and lacks an inner protrusion but has a surface coating.

[0028] Figure 15 A cross-sectional top view of an eighth example is shown, where the inner cylinder is coupled to the rear wall and lacks an inner protrusion but has a surface coating.

[0029] Figure 16 A cross-sectional top view of a ninth example is shown, where there is no additional seal beyond the inner cylinder, and where the inner cylinder is coupled to the rear wall and lacks an inner protrusion but has a surface coating.

[0030] Figure 17 A cross-sectional top view of a tenth example is shown, where there is no additional seal beyond the inner cylinder, but where there is a full-length outer cylinder, and where the inner cylinder is coupled to the front wall and lacks inner protrusions but has a surface coating.

[0031] Figure 18 A cross-sectional top view of an eleventh example is shown, where the inner cylinder is coupled to the front wall and has a plurality of inner protrusions, including an inner protrusion at an intermediate position.

[0032] Figure 19 A cross-sectional top view of a twelfth example is shown, where there is no additional seal beyond the inner cylinder, but where there is a full-length outer cylinder, and where the inner cylinder is coupled to the front wall and includes a rear protrusion.

[0033] Figure 20 A cross-sectional top view of a thirteenth example is shown, where the inner cylinder is coupled to the rear wall and has a plurality of inner protrusions, including an inner protrusion at an intermediate position.

[0034] Figure 21 A cross-sectional top view of a fourteenth example is shown, where there is no additional seal beyond the inner cylinder, but where there is a full-length outer cylinder, and where the inner cylinder is coupled to the front wall and includes a front protrusion.

[0035] Figure 22 A cross-sectional top view of a fifteenth example is shown, where the inner cylinder is coupled to the rear wall and has a hinge point on the wall portion, which is further separated from the outer cylinder.

[0036] Figure 23 A cross-sectional top view of a sixteenth example is shown, where the inner cylinder is coupled to the rear wall and has a varying diameter along the length.

[0037] Figure 24 A cross-sectional top view of a seventeenth example is shown, where the inner cylinder is coupled to the rear wall and obtains an inverted body as the lead body travels through the inner cylinder.

[0038] Figure 25 A cross-sectional top view of an eighteenth example is shown, where the inner cylinder and the outer cylinder are separate pieces that are joined together.

[0039] Figure 26 A cross-sectional side view of a front portion of a header including a seal is shown, where the inner cylinder is directly bonded to the lead hole of the header. DETAILED DESCRIPTION

[0040] Embodiments provide a seal for a lead bore of an implantable medical device and / or lead extension that allows for radial misalignment of a lead from centered alignment while maintaining a sealed engagement with a lead body of the lead.

[0041] Figure 1 An implantable medical system 100 is shown that includes an implantable medical device 102 and an implantable medical lead 104. The implantable medical device 102 includes a circuit housing 110 and a header 112 mounted to the circuit housing 110, which together form a complete device housing. The circuit housing 110 provides a sealed enclosure for a circuit 114 and an associated battery 116 that powers the circuit. The circuit 114 can include a stimulation engine capable of generating stimulation pulses. The circuit 114 can also or alternatively include a sensing circuit capable of receiving physiological signals. Examples of implantable medical devices 102 include, but are not limited to, neurostimulators such as those used for deep brain, spinal cord, pelvic, or peripheral nerve sensing and / or stimulation. Such devices can be used to deliver electrical stimulation therapy (and in some cases also a therapeutic agent) to various tissue sites of a patient to treat a variety of symptoms or conditions such as chronic pain, tremor, Parkinson's disease, other movement disorders, epilepsy, urinary or fecal incontinence, sexual dysfunction, obesity, or gastroparesis. In other examples, such devices can be cardiac devices used to deliver electrical stimulation to a heart.

[0042] To communicate electrical signals, the circuit 114 has electrical connections 118 that establish an electrical pathway with conductors 120 present within the header 112. The electrical connections 118 can include feedthroughs that allow the electrical pathway to transition between the interior of the circuit housing 110 and the interior of the header 112 while maintaining a sealed relationship between the circuit housing 110 and the header 112.

[0043] The header 112 provides a lead bore 124 that includes a set of electrical connectors 122. The conductors 120 are electrically coupled to corresponding electrical connectors 122 to deliver electrical signals. The lead bore 124 also includes a set of seals 123 interleaved with the electrical connectors 122. The front seal 126 of this example also provides an outer surface for the header 112 in the area at the opening of the lead bore 124. In this particular example, there is a second lead bore that also contains electrical connectors with interleaved seals. While the conductors 120, electrical connectors 122, and seals 123 are visible in Figure 1 they are enclosed with the header 112 in a sealed arrangement by a layer of liquid silicone rubber or other similar material.

[0044] A proximal end of the implantable medical lead 104 is shown. On this proximal end, the lead includes proximal contacts 106 that are mounted to a lead body 108. These proximal contacts are conductors, such as metal rings. Conductors within the lead body 108 electrically couple the proximal contacts 106 to distal electrodes located on a distal end of the lead 104.

[0045] The proximal end of the lead 104 is inserted into the lead bore 124 of the implantable medical device 102 and / or lead extension. Each proximal contact 106 is electrically coupled to a corresponding electrical connector 122. Each seal 123 engages the lead body 108 between adjacent proximal contacts 106. The front seal 126 engages the lead body 108 distal of the distal-most proximal contact 106. In this example, because the front seal 126 provides the outer surface of the header 112 at the lead bore 124, the front seal 126 includes an opening 128. This example of the lead 104 also includes a surface coating 109, such as a silicone or parylene coating, to reduce friction as the lead body 108 passes through the front seal 126. This surface coating 109 can be effective for certain configurations of the front seal 126, such as Figures 13 to 17 The illustrated example, which is discussed in greater detail below.

[0046] Figures 2 to 6 Various perspective and cross-sectional views of the front seal 126 are shown. The front seal is at least partially elastomeric, including at least a portion that is compliant so as to receive and form a seal against the lead body 108. Examples of elastomeric materials suitable for the front seal 126 or the elastomeric portion of the front seal 126 (if not all of the front seal 126 is elastomeric) include biocompatible materials having a modulus of elasticity value, such as the modulus of elasticity values specified in the data sheet entitled "BioMedical Grade Liquid Silicone Rubbers" from Dow Corning Corporation (copyright 2002-2006) in the range of 100 pounds per square inch to 1000 pounds per square inch, or in another example in the range of 400 pounds per square inch to 700 pounds per square inch. Examples of suitable biocompatible materials include, but are not limited to, silicones and urethanes. BioMedical Grade Liquid Silicone Rubbers. In this example, the front seal 126 is formed from a single piece of the elastomeric material.

[0047] The opening 128 of the front seal 126 exists on a front wall portion 136 that provides the outer surface. In this example, the outer surface of the front wall portion 136 defines a plane, such as the plane discussed below with respect to Figure 7B and Figure 8B However, in other examples, the outer surface of the front seal 126 can not be planar. In this example, the front seal 126 also includes a front block 132, followed by a rear cylinder 134 and a rear flange 130. The rear flange 130, the rear cylinder 134, and the block 132 can engage corresponding receptacles in the header 112, thereby securing the proper position of the front seal 126 relative to the header 112.

[0048] As Figure 3and Figure 5 As best shown in the cross-sectional view, the front seal 126 includes several internal features. An inner cylinder 138 is present at the opening 128 and defines a seal bore through which the lead body 108 is placed. The inner cylinder 138 is attached to the front wall 126 at the front end. A block 132 forms an outer cylinder coupled to the wall portion 136 and defining an outer seal bore. Because the outer seal bore formed by the block 132 has an inner diameter that is larger than the outer diameter of the inner cylinder 138, the block 132 is separated from the inner cylinder 138 by a gap 150. In this example, the inner and outer cylinders of the block 132 are concentric such that the gap 150 has a uniform size around the circumference, but can be non-concentric in other examples.

[0049] The wall portion 136 defines a transition portion 152 between the end of the inner cylinder 138 and the end of the outer cylinder defined by the block 132. Because the back end of the inner cylinder 138 is unattached, the transition portion 152 acts as a hinged connection of the inner cylinder 138 to the wall portion 136 and the block 132. Because the front seal 126 is at least partially elastomeric, the transition portion 152 allows the back end of the inner cylinder 138 to have freedom of movement within the gap 150, which allows the inner cylinder 138 to remain in sealing engagement with the lead body 108 as the lead body 108 can move about.

[0050] In some examples, including Figure 2 To the example shown in FIG. 8, sealing protrusions 144 and 146 can be provided at the back of the inner cylinder 138 that extend radially inward into the outer seal bore of the block 132 to further seal and support the lead body 108. However, such protrusions 144, 146 can create gaps relative to the lead body 108 as the lead body 108 moves in various radial directions, but the presence of the inner cylinder 138 prevents leakage that might otherwise occur through such gaps. This phenomenon is shown in Figures 7A to 8B and described below.

[0051] In the example shown in Figures 2 to 8B , the opening 128 provides a seal protrusion 140. The inner cylinder 138 of the front seal 126 also includes an additional, relatively small protrusion 142 in a rearward position. Because the inner cylinder 138 has freedom of movement relative to the rest of the front seal 126, the protrusion 142 remains fully engaged around the circumference of the lead body 108 during radial movement.

[0052] Figure 7AThe lead body 108 is shown as present within the front seal 126. Here, the lead body 108 is centrally aligned within the front seal 126. As such, all of the seal engagements including the protrusion 140, the inner cylindrical protrusion 142, the protrusion 144, and the protrusion 146 are fully circumferentially engaged with the lead body 108.

[0053] This presence presents a situation as shown in Figure 7B where the centerline 172 of the inner cylinder 138 of this example is perpendicular to the plane 170 according to a right angle 174. This plane 170 can be established by the outer surface of the wall portion 136. Alternatively, this plane 170 can not be established by a physical object, but can simply exist in free space for the purpose of providing a geometric relationship with the inner cylinder 138 and the centerline 172. As noted above, the inner cylinder 138 can have a rest state that is centrally aligned such that the centerline forms a right angle with respect to the plane 170, as shown in Figure 3 , and this state is maintained when the lead body 108 is also centrally aligned as shown in Figure 7A . Alternatively, the inner cylinder 138 can have a rest state that provides the centerline at a different angle with respect to the same plane 170. This different angle of the rest state can correspond to a centrally aligned lead 108 or can correspond to a non-centrally aligned lead body 108, such that a centrally aligned lead body 108 can move the inner cylinder to a non-rest state position. In either case, a radial movement of the lead 108 out of central alignment can result in the centerline of the inner cylinder 138 achieving yet another angle with respect to the plane 170.

[0054] Figure 8A The lead body 108' is shown as present within the front seal 126 but has been radially moved out of central alignment. In this case, it can be seen that small gaps 160, 162 are formed with respect to the protrusions 144' and 146'. However, because the inner cylinder 138 has freedom of movement due to the free end, the compliant transition portion 152', and the gap 150' between the inner cylinder 138' and the outer cylinder of the block 132, the inner cylinder 138 has remained fully engaged around the entire circumference of the lead body 108. In this example, both the protrusion 140 and the protrusion 142 remain sealed against the lead body 108.

[0055] This presence presents a situation as shown in Figure 8B where the centerline 172' of the inner cylinder 138 of this particular example is no longer perpendicular to the plane 170 according to an acute angle 176. As noted above, this plane 170 can be established by the outer surface of the wall portion 136. Alternatively, this plane 170 can not be established by a physical object, but can simply exist in free space for the purpose of providing a geometric relationship with the inner cylinder 138' and the centerline 172'.

[0056] While the discussion is in relation to the front seal 126, it should be understood that similar structures including the inner cylinder 138 can be used at other sealing locations within the head 112. Further, it should be understood that while the inner cylinder 138 is shown positioned at the front of the front seal 126 to form the outer opening 126, the sealing orientation can be reversed with the inner cylinder 138 positioned on the rear side of the front seal 126. It should also be understood that while this example shows a single inner cylinder 138, multiple inner cylinders can be used, such as one at the front of the front seal 126 and another at the rear of the front seal 126. Additional variations are discussed below with respect to Figures 9 to 24 FIGS. 4-6.

[0057] Figure 9 An example of a seal 202 is shown that includes an inner cylinder 206 with a transition 210 at a front wall 212. The seal 202 defines a bore opening 204 and has a gap 208 between the inner cylinder 206 and an outer cylinder formed by the seal body. The inner cylinder 206 of this example includes an inner protrusion 214 at a rear end. In this example, the rear end 216 of the inner cylinder 206 is also asymmetric in that it is angled relative to a plane that is perpendicular to the centerline of the inner cylinder 206. This example also includes additional seals 218, 220 and defines a rear opening 222.

[0058] Figure 10 An example of a seal 302 is shown that includes an inner cylinder 306 with a transition 310 at a front wall 312. The seal 302 defines a bore opening 304 and has a gap 308 between the inner cylinder 306 and a head structure that surrounds the seal body. The inner cylinder 306 of this example includes an inner protrusion 314 at a rear end. In this example, the rear end 316 of the inner cylinder 306 is also asymmetric in that it is angled relative to a plane that is perpendicular to the centerline of the inner cylinder 306. This example lacks any additional seals and the inner cylinder 306 defines a rear opening 318 of the seal.

[0059] Figure 11 An example of a seal 402 is shown that includes an inner cylinder 406 with a transition 410 at a rear wall. A front wall 412 of the seal 402 defines a bore opening 404. A gap 408 is formed between the inner cylinder 406 and an outer cylinder formed by the seal body. The inner cylinder 406 of this example includes an inner protrusion 414 at a front end 416. In this example, the front end 416 of the inner cylinder 406 is also asymmetric in that it is angled relative to a plane that is perpendicular to the centerline of the inner cylinder 406. This example also includes additional seals 418, 420 and the inner cylinder 406 defines a rear opening 422 of the seal.

[0060] Figure 12 An example of a seal 502 is shown that includes an inner cylinder 506 with a transition 510 at the back wall. The front end 512 of the inner cylinder 506 defines the hole opening 504. The seal 502 has a gap 508 between the inner cylinder 506 and the head structure that surrounds the seal body. The inner cylinder 506 of this example includes an inner protrusion 514 at the front end 516. In this example, the front end 516 of the inner cylinder 506 is also asymmetric in that it is angled relative to a plane that is perpendicular to the centerline of the inner cylinder 506. This example lacks any additional seals, and the back wall of the seal 502 defines the back opening 518 of the seal.

[0061] Figure 13 An example of a seal 602 is shown that includes an inner cylinder 606 with a transition 610 at the front wall 612. The seal 602 defines the hole opening 604 and has a gap 608 between the inner cylinder 606 and the outer cylinder formed by the seal body. The inner cylinder 606 of this example lacks an inner protrusion that would result in more complete contact with the lead body over the length of the inner cylinder 606. To facilitate entry and exit of the lead body through the cylinder 606, the inner surface of the cylinder 606 can include a surface coating 614 to provide lower friction. Examples of such surface coatings include silicone and parylene. As noted above with respect to Figure 1 instead of or in addition to the surface coating 614, the lead body 108 can include a surface coating 109 to reduce friction. This example also includes additional seals 618, 620 and defines a back opening 622.

[0062] Figure 14 An example of a seal 702 is shown that includes an inner cylinder 706 with a transition 710 at the front wall 712. The seal 702 defines the hole opening 704 and has a gap 708 between the inner cylinder 706 and the head structure that surrounds the seal body. The inner cylinder 706 of this example lacks an inner protrusion that would result in more complete contact with the lead body over the length of the inner cylinder 706. To facilitate entry and exit of the lead body through the cylinder 706, the inner surface of the cylinder 706 can include a surface coating 714 similar to the surface coating 614 of Figure 13 As noted above with respect to Figure 1 and Figure 13 instead of or in addition to the surface coating 714, the lead body 108 can include a surface coating 109 to reduce friction. This example lacks any additional seals, and the inner cylinder 706 defines the back opening 718 of the seal.

[0063] Figure 15An example of a seal 802 is shown that includes an inner cylinder 806 with a transition portion 810 at the back wall. The front wall 812 of the seal 802 defines the bore opening 804. A gap 808 is formed between the inner cylinder 806 and the outer cylinder formed by the seal body. The inner cylinder 806 of this example lacks an inner protrusion that would result in more complete contact with the lead body over the length of the inner cylinder 806. To facilitate entry and exit of the lead body through the cylinder 806, the inner surface of the cylinder 806 can include a surface coating 814 similar to the surface coating 614 of Figure 13 to provide lower friction. As described above with respect to Figure 1 and Figure 13 , instead of or in addition to the surface coating 814, the lead body 108 can include a surface coating 109 to reduce friction. This example also includes additional seals 818, 820, and the inner cylinder 806 defines a back opening 822 of the seal.

[0064] Figure 16 An example of a seal 902 is shown that includes an inner cylinder 906 with a transition portion 910 at the back wall. The front end 912 of the inner cylinder 906 defines the bore opening 904. The seal 902 has a gap 908 between the inner cylinder 906 and the head structure that surrounds the seal body. The inner cylinder 906 of this example lacks an inner protrusion that would result in more complete contact with the lead body over the length of the inner cylinder 906. To facilitate entry and exit of the lead body through the cylinder 906, the inner surface of the cylinder 906 can include a surface coating 914 similar to the surface coating 614 of Figure 13 to provide lower friction. As described above with respect to Figure 1 and Figure 13 , instead of or in addition to the surface coating 914, the lead body 108 can include a surface coating 109 to reduce friction. This example lacks any additional seals, and the back wall of the seal 902 defines a back opening 918 of the seal.

[0065] Figure 17 An example of a seal 1002 is shown that includes an inner cylinder 1006 that extends the full length of the seal 1002, and where an outer cylinder surrounds the inner cylinder 1006 over the full length of the seal 1002. The inner cylinder 1006 has a transition portion 1010 at the front wall 1012. The seal 1002 defines a bore opening 1004, and has a gap 1008 between the inner cylinder 1006 and the outer cylinder that surrounds the seal body. The inner cylinder 1006 of this example lacks an inner protrusion that would result in more complete contact with the lead body over the length of the inner cylinder 1006. To facilitate entry and exit of the lead body through the cylinder 1006, the inner surface of the cylinder 1006 can include a surface coating 1014 similar to the surface coating 614 of Figure 13surface coating 614 to provide lower friction. As noted above with respect to Figure 1 and Figure 13 Instead of or in addition to surface coating 1014, lead body 108 can include a surface coating 109 to reduce friction. This example lacks any additional seals, and inner cylinder 1006 defines a rear opening 1018 of the seal, although it exists within the full-length outer cylinder.

[0066] Figure 18 An example of a seal 1102 is shown that includes an inner cylinder 1106 with a transition 1110 at a front wall 1112. Seal 1102 defines a bore opening 1104, and has a gap 1108 between inner cylinder 1106 and an outer cylinder formed by the seal body. Inner cylinder 1106 of this example includes a first inner protrusion 1114 at the rear end, and has a second inner protrusion 1115 at an intermediate location to provide additional sealing surfaces. It will be appreciated that any number of additional inner protrusions can be included, such as a third inner protrusion provided at opening 1104. This example also includes additional seals 1118, 1120 and defines a rear opening 1122.

[0067] Figure 19 An example of a seal 1202 is shown that includes an inner cylinder 1206, and where the outer cylinder that surrounds inner cylinder 1206 is full-length of seal 1202. Inner cylinder 1206 has a transition 1210 at a front wall 1212. Seal 1202 defines a bore opening 1204, and has a gap 1208 between inner cylinder 1206 and an outer cylinder that surrounds the seal body. Inner cylinder 1206 of this example includes an inner protrusion 1214 at the rear end. This example lacks any additional seals, and inner cylinder 1206 defines a rear opening 1222 of the seal.

[0068] Figure 20 An example of a seal 1302 is shown that includes an inner cylinder 1306 with a transition 1310 at a rear wall. A front wall 1312 of seal 1302 defines a bore opening 1304. A gap 1308 is formed between inner cylinder 1306 and an outer cylinder formed by the seal body. Inner cylinder 1306 of this example includes a first inner protrusion 1314 at the front end, and has a second inner protrusion 1315 at an intermediate location to provide additional sealing surfaces. It will be appreciated that any number of additional inner protrusions can be included, such as a third inner protrusion provided at opening 1322. This example also includes additional seals 1318, 1320, and inner cylinder 1306 defines a rear opening 1322 of the seal.

[0069] Figure 21An example of a seal 1402 is shown that includes an inner cylinder 1406 and where the outer cylinder that surrounds the inner cylinder 1406 is the full length of the seal 1402. The inner cylinder 1406 has a transition portion 1410 at the back wall. The inner cylinder 1406 defines the aperture opening 1404 and has a gap 1408 between the inner cylinder 1406 and the outer cylinder that surrounds the seal body. The inner cylinder 1406 of this example includes an inner protrusion 1414 at the front end. This example lacks any additional seals and the inner cylinder 1406 also defines the back opening 1422 of the seal.

[0070] Figure 22 An example of a seal 1502 is shown that includes an inner cylinder 1506 with a transition portion 1510 at the front wall 1512. The transition portion 1510 of this example creates a relatively large gap 1508 from the inner cylinder 1506 to the outer cylinder at the hinge point of the inner cylinder 1506 provided by the transition portion 1510. The seal 1502 defines the aperture opening 1504. The inner cylinder 1506 of this example includes an inner protrusion 1514 at the back end. This example also includes additional seals 1518, 1520 and defines a back opening 1522. Similar to the example described above, the seal configuration can also be reversed such that the inner cylinder 1506 is pre-set at the back of the seal instead of the front. Further, the large space provided by the transition portion 1510 can be provided where only the inner cylinder 1506 provides a seal to the lead body and where the additional seals such as seals 1518 and 1520 are omitted.

[0071] Figure 23An example of a seal 1602 is shown that includes an inner cylinder 1606 with a transition 1610 at a front wall 1612. The inner cylinder 1606 of this example includes a diameter that varies over the length of the inner cylinder 1606. As can be seen in this particular example, the diameter varies in a manner that continuously decreases from the front end to the back end of the inner cylinder 1606, although it should be understood that the diameter can vary over the length in any number of ways, such as having a minimum diameter at an intermediate position or at the front end. This particular example can form a seal with a tighter fit to the lead body 108 at the protrusion 1614. The seal 1602 defines a bore opening 1604 and has a gap 1608 between the inner cylinder 1606 and an outer cylinder formed by the seal body. The inner cylinder 1606 of this example includes a first inner protrusion 1614 at the back end and a second inner protrusion 1616 at the front end, which is provided with the bore opening 1604. This example also includes additional seals 1618, 1620 and defines a back opening 1622. Similar to the examples described above, the seal configuration can also be reversed, such that the inner cylinder 1606 is provided at the back of the seal rather than the front. Further, a varying diameter of the inner cylinder 1606 can be provided, where only the inner cylinder 1606 provides a seal to the lead body, and where the additional seals such as seals 1518 and 1520 are omitted.

[0072] Figure 24 An example of a seal 1702 is shown that includes an inner cylinder 1706 with a transition 1710 at a front wall 1712. The transition 1710 of this example creates a relatively large gap 1708 from the inner cylinder 1706 to the outer cylinder at the hinge point of the inner cylinder 1706 provided by the transition 1710, similar to the case of Figure 22 However, in this example, the inner cylinder 1706 forms an inversion 1716 and results in a most inner cylinder portion 1707 that defines an opening 1705 and a second opening 1709. This most inner cylinder portion 1707 can create a tighter seal to the lead body 108. The inner cylinder 1706 of this example includes an inner protrusion 1714 at the back end. The inversion 1716 can be present in a rest state of the seal 1702, or the inversion 1716 can be created by the lead body moving through the inner cylinder 1706 as described below. The seal 1702 defines a bore opening 1704. This example also includes additional seals 1718, 1720 and defines a back opening 1722. Similar to the examples described above, the seal configuration can also be reversed, such that the inner cylinder 1706 is provided at the back of the seal rather than the front. Further, a large space provided by the transition 1710 can be provided, where only the inner cylinder 1706 provides a seal to the lead body, and where the additional seals such as seals 1718 and 1720 are omitted.

[0073] As described above, the inverted body can exist in the static state of the seal 1702, or it can be generated by the movement of the lead body. Regarding the inner cylinder 1716 forming the hole opening 1704... Figure 24 In the illustrated orientation, in the example where the movement of the lead body generates an inverted body, the seal 1702 can be in a stationary state, with the lead 104 fully inserted. In this stationary state, there is no inverted body 1716, leaving only the inner cylinder 1706. However, upon movement in the outward direction, the movement of the lead body 108 pulls the inner cylinder 1716 to form the inverted body 1716 and the innermost cylinder 1707.

[0074] In Figure 24 In the opposite orientation shown, the inner cylinder 1716 forms the rear opening of the seal, and the seal 1702 can be stationary before the lead 104 is inserted. In this stationary state, there is no inverted body 1716, so only the inner cylinder 1706 exists. When the lead 104 is inserted and moves through the inner cylinder 1706 in the insertion direction, the movement of the lead body 108 pulls the inner cylinder 1716 to form the inverted body 1716 and the innermost cylinder 1707.

[0075] Figure 25 An example of a seal 1802 is shown, which includes an inner cylinder 1806 having a transition portion 1810 at a front wall 1812. The seal 1802 defines an opening 1804 and has a gap 1808 between the inner cylinder 1806 and an outer cylinder 1801 formed by a sealing body. In this example, the inner cylinder 1806 includes an inner protrusion 1814 at its rear end. This example also includes additional seals 1818 and 1820 and defines a rear opening 1822. Similar to the example above, the seal configuration can also be reversed, such that the inner cylinder 1806 is positioned at the rear of the seal instead of the front. Furthermore, space provided by the transition portion 1810 can be provided where only the inner cylinder 1806 provides a seal to the lead body, and where additional seals such as seals 1818 and 1820 are omitted.

[0076] exist Figure 25It is particularly noted that at least a portion of the outer cylinder 1801 and / or the wall portion of the seal 1802 is constructed of a first material having a first modulus of elasticity value, while the inner cylinder 1806 is constructed of a second material having a second modulus of elasticity value. For example, in one example, the outer cylinder 1801 and at least a portion of the wall portion can have a modulus value higher than 700 pounds per square inch, while the inner cylinder 1806 can have an elastic modulus value lower than 700 pounds per square inch, such as specified in the previously introduced Dow Corning data sheet. In the case of using two different materials, the outer cylinder 1801 and / or at least a portion of the wall portion can have an elastic modulus value far exceeding the range of elastic modulus values of the inner cylinder 1806 previously specified, such as where the inner cylinder elastic modulus value continues to fall within the previously introduced range of 100 pounds per square inch to 1000 pounds per square inch, while the outer cylinder 1801 and / or at least a portion of the wall portion can have an elastic modulus value exceeding 10,000 pounds per square inch. The two materials are joined at the junction 1824, and the outer cylinder 1801 forms an additional wall region 1826, where the wall portion 1812 has a smaller elastic modulus value than the elastic modulus value of the wall portion 1826. One way of joining the two materials together includes utilizing a primer, such as a silicone coating covered with a silicone medical adhesive, and then allowing the second material to overmold into the interior of the outer cylinder 1801 to form the inner cylinder 1806.

[0077] Figure 26 An example of a front portion of a head 1900 of an implantable medical device is shown. The head 1900 includes a head body 1901 that is typically constructed of a rigid biocompatible polymer such as a polysulfone or a polyether ether ketone (PEEK). A seal 1902 is present within a lead bore 1928 of the head body 1901. In this example, there is no outer cylinder, and the wall portion 1912 of the seal 1902 is directly bonded to the cylindrical wall of the lead bore 1928. This example also shows an additional alternative where the head body 1901 has been coated with a layer 1926 of an elastic material such as silicone that also enters the lead bore 1928 to form the seal 1902. The exterior of the lead bore 1928 and / or the lead body 1901 can be primed with a silicone such as a silicone medical adhesive to allow for bonding of the coating forming the layer 1926 to the seal 1902.

[0078] This example of the seal 1902 includes an inner cylinder 1906 with a transition portion 1910 at a front wall 1912. The seal 1902 defines a bore opening 1904 and has a gap 1908 between the inner cylinder 1906 and a lead bore 1928. The inner cylinder 1906 of this example includes an inner protrusion 1914 at the rear end. This example omits any additional seals, but can include these as an alternative. Similar to the above examples, the seal configuration can also be reversed such that the inner cylinder 1906 meets the transition portion 1910 at the rear, rather than the front, of the seal 1902.

[0079] The embodiments described above in Figures 1 to 26 The embodiments described above in

[0080] In one example, an implantable medical device includes a housing defining a lead bore having a lead bore diameter, a circuit within the housing, an electrical connector positioned within the lead bore and electrically coupled to the circuit, and a seal body coupled to the housing. The seal body includes a first cylinder that is elastic and defines a seal bore having a centerline, the first cylinder positioned within the lead bore and having an outer diameter at a location of the first cylinder that is less than the lead bore diameter, and a wall portion coupled to the housing, the wall portion coupled to the first cylinder and having an outer surface that forms a plane that intersects the centerline, the first cylinder movable relative to the wall portion to allow a change in an intersection angle between the centerline and the plane.

[0081] In this example, the sealing body can further include a protrusion present around a circumference of the sealing bore and extending radially inward into the sealing bore. The sealing body can further include a second cylinder coupled to the wall portion, the second cylinder defining an outer sealing bore having an inner diameter greater than an outer diameter of the first cylinder such that the second cylinder encloses the first cylinder. The second cylinder can extend beyond an end of the first cylinder, and wherein the second cylinder further includes a protrusion present around a circumference of the outer sealing bore and extending radially inward into the outer sealing bore. The first and second cylinders can be concentric. At least the first cylinder of the elastomeric sealing body can have an elastic modulus value in a range of 100 pounds per square inch to 1000 pounds per square inch. At least the first cylinder of the elastomeric sealing body can have an elastic modulus value in a range of 400 pounds per square inch to 700 pounds per square inch. At least the first cylinder of the sealing body can comprise silicone. At least the first cylinder of the sealing body can comprise urethane. The first cylinder can be positioned at a front of the sealing body. The first cylinder can be positioned at a back of the sealing body. The first cylinder can include a diameter that varies over a length of the first cylinder. The first cylinder can include an inverse. The first cylinder can include a plurality of protrusions extending radially inward into the sealing bore. The first cylinder can include an asymmetric front end. The first cylinder can include an asymmetric back end. The first cylinder can include a surface coating. The second cylinder can be less than a full length of the sealing body. The sealing body can include a flange. The first cylinder can comprise a first material and at least a portion of the wall portion comprises a second material, and wherein the first material has a lower elastic modulus value than the second material.

[0082] In another example, a seal for an implantable medical device can include a body comprising: a first cylinder that is elastomeric and defines a sealing bore having a centerline, the first cylinder having an outer diameter; and a wall portion coupled to the first cylinder, wherein the first cylinder has a rest position in which the centerline forms a first angle relative to a first plane, the first cylinder being movable relative to the wall portion to allow the first angle of the centerline relative to the first plane to change.

[0083] In another example, an implantable medical device can include a housing defining a lead bore having a lead bore diameter, a circuit within the housing, an electrical connector positioned within the lead bore and electrically coupled to the circuit, and a sealing body coupled to the housing. The sealing body can include a first cylinder that is elastic and defines a sealing bore having a centerline, the first cylinder positioned within the lead bore and having an outer diameter at a location of the first cylinder that is less than the lead bore diameter, and a wall portion coupled to the housing, the wall portion coupled to the first cylinder, wherein the first cylinder has a rest position in which the centerline forms a first angle with respect to a first plane, the first cylindrical portion movable with respect to the wall portion to allow the first angle of the centerline with respect to the first plane to change.

[0084] While embodiments have been particularly shown and described, it will be understood by those skilled in the art that various other modifications in form and details can be made therein without departing from the essence and scope of the application.

Claims

1. A seal for an implantable medical device, comprising: a body comprising: a first cylinder that is elastic and defines a sealing bore having a centerline, the first cylinder having an outer diameter; and a wall portion coupled to the first cylinder and having an outer surface that forms a plane that intersects the centerline, the first cylinder being movable relative to the wall portion to allow a change in an intersection angle between the centerline and the plane.

2. The seal of claim 1, further comprising a protrusion that exists around a circumference of the sealing bore and extends radially inward into the sealing bore.

3. The seal of either of claims 1 or 2, further comprising a second cylinder coupled to the wall portion, the second cylinder defining an outer sealing bore having an inner diameter that is greater than the outer diameter of the first cylinder such that the second cylinder encloses the first cylinder.

4. The seal of claim 3, wherein the second cylinder extends beyond an end of the first cylinder, and wherein the second cylinder further comprises a protrusion that exists around a circumference of the outer sealing bore and extends radially inward into the outer sealing bore.

5. The seal of either of claims 3 or 4, wherein the first cylinder and the second cylinder are concentric.

6. The seal of any of claims 1 to 5, wherein at least the first cylinder of the body has an elastic modulus value in a range of 100 pounds per square inch to 1000 pounds per square inch.

7. The seal of any of claims 1 to 6, wherein at least the first cylinder of the body has an elastic modulus value in a range of 400 pounds per square inch to 700 pounds per square inch.

8. The seal of any of claims 1 to 7, wherein at least the first cylinder of the body comprises silicone.

9. The seal of any of claims 1 to 7, wherein at least the first cylinder of the body comprises urethane.

10. The seal of any of claims 1 to 9, wherein the first cylinder comprises a first material and at least a portion of the wall portion comprises a second material, and wherein the first material has a lower elastic modulus value than the second material.

11. An implantable medical device, comprising: a housing defining a lead bore having a lead bore diameter; circuitry within the housing; an electrical connector positioned within the lead bore and electrically coupled to the circuitry; and a sealing body coupled to the housing, the sealing body comprising: a first cylinder that is elastic and defines a sealing bore having a centerline, the first cylinder being positioned within the lead bore and having an outer diameter at a location of the first cylinder that is less than the lead bore diameter; and a wall portion coupled to the first cylinder and having an outer surface that forms a plane that intersects the centerline, the first cylinder being movable relative to the wall portion to allow a change in an intersection angle between the centerline and the plane. a wall portion coupled to the housing, the wall portion being coupled to the first cylinder and having an outer surface that forms a plane that intersects the centerline, the first cylinder being movable relative to the wall portion to allow a change in an intersection angle between the centerline and the plane.

12. The implantable medical device of claim 11, wherein the seal body further comprises a protrusion that is present around a circumference of the seal bore and extends radially inward into the seal bore.

13. The implantable medical device of any one of claims 11 or 12, wherein the seal body further comprises a second cylinder coupled to the wall portion, the second cylinder defining an outer seal bore having an inner diameter that is greater than an outer diameter of the first cylinder, such that the second cylinder encloses the first cylinder.

14. The implantable medical device of claim 13, wherein the second cylinder extends beyond an end of the first cylinder, and wherein the second cylinder further comprises a protrusion that is present around a circumference of the outer seal bore and extends radially inward into the outer seal bore.

15. The implantable medical device of any one of claims 13 or 14, wherein the first cylinder and the second cylinder are concentric.

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